Systemic ALA with Light

The porphyrins produced by P acnes in the sebaceous follicle are in small quantities, and exogenous ALA has been shown to concentrate in sebaceous units [13]. Intraperitoneal injection of ALA into albino mice was shown to result in the accumulation of protoporphy­rin IX (PpIX) in the sebaceous glands of normal skin such that exposure to light of the appropriate wavelength destroyed the sebaceous glands [13]. Experiments aimed at char­acterizing the intracellular localization of PpIX in sebocytes following ALA application have shown that the fluorescence localizes in cellular membranes and distinctive spots, though efforts at identifying these intracellular spots have been unsuccessful [14]. While these data suggest that systemic ALA is highly effective at targeting sebaceous glands, this systems, approach is hampered by the side effect of prolonged photosensitivity.